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effective

adj. · n.
US //ˈifɛktɪv// UK //ɪfˈɛktɪv// ef·fec·tive
  1. 1 successful in producing a result (adj.)
    B1 Intermediate

    producing the result that you wanted or intended.

    successful in producing a desired or intended result. Often used to describe solutions, treatments, or methods.

    Example

    The new medicine was very effective at reducing her headache quickly.

    Example

    The marketing campaign proved highly effective, resulting in a twenty percent increase in new subscriptions over the first quarter.

    Usage

    Commonly modifies nouns like 'method', 'solution', 'treatment', or 'way'.
    Pitfall
    He is a very effective worker because he never wastes time.
    He is a very efficient worker because he never wastes time.

    Use 'effective' for things that get the right result; use 'efficient' for things that work quickly without wasting time or effort.

  2. 2 starting to apply or operate (adj.)
    B2 Upper Intermediate Formal Law

    starting to be used or starting to be a law.

    coming into operation or effect; officially in use or valid from a specific time.

    Example

    The new tax rules will be effective from the first of January.

    Example

    The revised safety regulations become effective immediately, and all site managers must ensure compliance by the end of the business day.

    Usage

    Often followed by the preposition 'from' when indicating a start date.
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  1. 3 actual or real (adj.)
    C1 Advanced Academic

    the real or actual situation, even if it is not the official one.

    existing in fact, though not necessarily intended or officially acknowledged.

    Example

    Although he is the assistant, he is the effective leader of the team.

    Example

    The effective cost of the loan was much higher than the advertised interest rate once the hidden fees were included.

    Teacher's tip

    In academic contexts, this sense contrasts 'effective' (the reality) with 'nominal' (the name or theory).
  2. 4 soldiers fit for duty (n.)
    C2 Proficiency Technical Formal Military

    a soldier who is healthy and ready to fight.

    a soldier or member of a military unit who is fit for active service.

    Example

    The general counted his effectives before the morning march.

    Example

    After the long winter campaign, the regiment's total number of effectives had dropped to less than half of its original strength.
Origin

From French effectif, from Latin effectīvus (“productive; effective”), from efficiō (“I make; I bring about”), equivalent to effect + -ive.

Word family

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